Automatic drainage apparatus



Patented Feb. 22, 1949 AUTOMATIC DRAINAGE APPARATUS Chauncey 0. De Witt, Teaneck, N. J., assigner to The Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application December 16, 1946, Serial No. 716,595

6 Claims.

This invention relates to automatic drainage apparatus for discharging condensate from uid pressure reservoirs, and more particularly to an automatically timed drain valve apparatus arranged to operate at intervals dependent upon the rate of accumulation of condensate in said reservoir.

Fluid under pressure supplied from a fluid compressor to a reservoir is usually substantially cooled while being stored therein, with the result that much of its vapor content condenses out. If the condensate is allowed to accumulate in the reservoir, it not only steals fluid pressure storage volume from said reservoir, but may find its way into a system utilizing fluid under pressure therefrom and cause operational failure or damage to the equipment comprised in said system.

Since the rate of accumulation of condensate in a reservoir is largely proportional to the rate of supply of fluid under pressure to said reservoir, it is desirable under certain conditions of operation, dependent upon climate and type of service etc., to provide an automatic drainage apparatus which will operate to discharge condensate from the reservoir at intervals in accordance with the rate of accumulation of said condensate in said reservoir, and it is a principal object of this invention to provide an improved apparatus of the above nature.

Other objects and advantages of the invention will hereinafter be apparent from the following more detailed description thereof.

Description In the accompanying drawing, the single figure is a schematic View, partly in outline and partly in section, of a iluid pressure system embodying the invention.

Referring to the drawing, the uid pressure system comprises a steam operated two stage fluid compressor device I of well known construction, a fluid pressure reservoir 2, a uid pressure actuated drain valve device 3, a check valve device 4, a timing reservoir 5, a timing valve device 6, and an exhaust choke 1.

The compressor I comprises a low pressure cylinder 8 and a high pressure cylinder 9 for `compressing fluid. A pipe III connects the high pressure cylinder v9 with the reservoir 2.

The drain valve device 3, mounted on the bottom of the reservoir 2, comprises a casing divided into portions II and I2. A resilient diaphragm I3 is disposed between the casing portions II and I2 in a tilted position forming a movable partition between a drain valve pressure chamber I4 in the casing portion I2 and a condensate exhaust chamber I5 in the casing portion I I, which latter chamber is open to an exhaust pipe and passage I6. A condensate collecting chamber I'I, formed in the casing portion II, is open to the interior of the reservoir 2 at the lowermost portion thereof by way of a passage I8. A bore I9 connects the lchamber I'I with a valve chamber 20 which is also formed in the casing portion II and which communicates by way of a bore 2I with the exhaust chamber I5. A double valve element 22, disposed within the valve chamber 20, is adapted at one end to cooperate with a valve seat 23 for controlling communication between the chambers I1 and 20, and is adapted at its opposite end to cooperate with a valve seat 24 for controlling communication between the exhaust chamber I5 and the valve chamber 20. Fluted stems 25 and 26, slidably mounted in the bores I9 and 2|, respectively, act to support and guide the double valve element 22 and also act as mediums through which said valve element may be actuated. The stem 2B is urged against a diaphragm surface plate y2'I by a light compression spring 28 arranged in the chamber I1 to act against the upper end of the uted stem 25. A compression control spring 29 is disposed in the exhaust chamber I5 and arranged to bear against the surface plate 21 to urge the diaphragm I3 toward an annular shoulder 30 formed in the casing portion I2. An annular rib 3| is provided on the diaphragm I3 for cooperation with the shoulder 3B. The pressure 'chamber I4 is open to a drain valve control pipe and passage 32.

The check valve device 4 has an inlet which is open to a pipe 33 connected with the interior of the low pressure cylinder 8 of the fluid compressor I, and an outlet which is open to a pipe 34 connected with the interior of the timing reservoir 5. A ball check valve 35 is provided in the device 4, arranged to control communication abetween the inlet and the outlet of said device.

A choke 36 is provided in the pipe 33 for restricting communication between the timing reservoir 5 and the compressor I. A strainer 3l' precedes the choke 36 in the same pipe.

The timing valve device 6 comprises a cylindrical casing 40 having a bore 4I which is closed at one end by an integrally formed casing end wall 42 and at the opposite end by a removable end cover 43. A piston valve 44 is slidably mounted in the bore 4I in sealing engagement with the peripheral surface thereof. On one side of the piston 44 there is an atmospheric chamber 45 which is open to the atmosphere by way of atmospheric vent passage 46 in the end cover 43 and on the opposite side there is an inlet chamber 41 which communicates with the timing reservoir 5 by Way 0f a timing reservoir pipe 48 and an inlet passage 49 formed in the end wall 42. An annular seat rib 50 is formed in the wall 42 surrounding the passage 49, which rib projects into the chamber 41 for engagement with a resilient piston valve sealing gasket 5| carried by the piston 44. A compression control spring 52 is disposed in the chamber 45 and arranged to urge the piston 44 toward the seat rib 50. A guide sleeve portion 53 of the piston valve 44 is provided with an annular rib 54 for engagement with a gasket 55 provided on the inner face of the end cover 43. One end of a passage 56 in the casing 40 forms a port 51 which opens into the bore 4I adjacent to the end wall 42, while the opposite end of said passage forms a port 58 which opens into said ibore adjacent to the end cover 43. An outlet passage 59, connected to the drain valve pipe 32, opens into the passage 56. The valve 44 is so arranged within the bore 4| as to be operable to alternately cover and uncover the ports 51 and 58 to control ycommunication between the timing reservoir pipe 48 and the drain valve pipe 32, and between the drain valve pipe 32 and the atmospheric vent passage 46.

. The choke 1 is inserted in a fluid pressure atmospheric vent pipe 60 which pipe is connected tothe drain valve pipe 32 at one end and is open to atmosphere at the opposite end.

Operation .In opera-tion, assume that the compressor is not operating, that there is no fluid under pressure being supplied to the pipes I and 33 from the compressor, and that therefore the reservoir 2 contains no fluid under pressure. The ball check valve 35 in the pipe 33 is seated in the absence of fluid under pressure required to unseat it. The timing chamber is yet to be supplied with fluid under pressure, consequently in absence of any pressure of uid in the inlet passage 49 in the timing valve device 6, the spring 52 therein is maintaining the piston valve gasket 5I seated on the rib 50 surrounding said inlet passage. The port 51 is covered by the piston valve 44, thus the inlet passage 49 is closedrto the outlet passage 59. The port 58 is uncovered, thus the outlet passage 59 is open to the atmospheric vent passage 46, by Way of thepassage 56 and the chamber 45. The drain valve pipe 32 being connected to the outlet passage 59Y is now open to atmosphere through vent passage 46 as well as through vent pipe 6U by way of the choke l. The drain valve pressure chamber I4, to which the drain valve pipe 32 is open, is thereby also open to atmosphere and in the absence of any effective pressure of uid acting on the underside of the diaphragm I3 exposedto said chamber, the diaphragm rib 3| is seated'on ,the casing shoulder 30. The position of the diaphragm surface plate 21 on the seated diaphragmris such that the double valve element 22 is seated on the valve seat 24 by action of the spring 28. The collecting chamber |1 and connected valve chamber are thus' closed olf from the'exhaust chamber I5. The chambers I1 and 2B contain no condensate since the reservoir 2 to which they are now open is yet to receive fluid under pressure.

Now assume that the compressor I is'started and that therefore the high pressure cylinder 9 is discharging fluid under pressure into the pipe I0, thus supplying fluid under pressure to the reservoir 2 at a rate dependent upon the speed of the compressor. Any condensate collecting in the reservoir 2 will be draining into the condensate collecting chamber I1 and the valve chamber 29 at a rate dependent upon the rate of supply of fluid 4under pressure to said reservoir.

At the same time, the pipe 33 is being supplied by the low pressure cylinder 8 with a fraction of the total amount of fluid handled by the compressor I. This uid passes through the strainer device 31, the choke 36, and the check valve device 4 and into the timing reservoir 5 where it is retained by the action of the spring 52 on the piston valve 44. In the timing reservoir 5 the fluid accumulates and increases in pressure at a rate dependent upon the speed of the compressor and the flow capacity of the choke 36.

The fluid at prevailing timing reservoir pressure acts on the area of the piston valve gasket 5I within the rib 50, and when the effect of said pressure thus acting thereon becomes great enough to overcome the opposing force of the spring 52, the piston valve moves away from the rib 50. Fluid under pressure from the timing reservoir 5 then enters the inlet chamber 41, acts on the entire face area of the valve 44, and rapidly moves said piston valve further away from the rib 50 against the opposing action of the spring 52 to an opposite seated position defined by contact of the rib 54 with the gasket 55 on the end cover 43. The piston valve 44, in its rapid movement toward the end cover 43, covers the port 58 to close olf the drain valve pipe 32 from the atmospheric vent passage 46, and uncovers the port 5l thus opening the drain valve pipe 32 to the timing reservoir 5 and allowing fluid under pressure to flow from said reservoir into said pipe whence it flows into the drain valve chamber I4.

Fluid under pressure being supplied to the drain valve chamber I4 acts on the limited under surface of the diaphragm I3 Within the rib 3|. When the force of the pressure of iluid thus acting on the diaphragm becomes suiciently great to overcome the opposing force of the spring 29 acting on top of the diaphragm, the diaphragm rib 3| parts from casing shoulder 30 thereby exposing the entire pressure surface of the diaphragm to said fluid under pressure. Upon such additional exposure, the diaphragm I3, attached surface plate 21, and associated valve elements are caused to quickly move away from the shoulder 30 to a position limited by Contact of the valve element 22 with the valve seat 23. In traversing the distance between the two seats 24 and 23, the double valve element 22 permits the pressure of fluid in the reservoir 2 to force any condensate that has accumulated during this time from the chambers I 1 and 20 through the chamber I5 and out the condensate exhaust pipe and passage I6. This discharge of condensate is rapid, so that only a small amount of fluid under pressure from the reservoir 2 is required for the operation.

Meanwhile the pressure of fluid acting on the piston valve 44 in the inlet chamber 4l of the valve device 6 has been escaping through the choke 'I in the atmospheric vent pipe 60 connected to the drain valve pipe 32 at a rate eX- ceeding the rate of supply of iiuid under pressure to said chamber 41 from the timing reservoir 5 supplied from the compressor I through the choke 36. When the pressure of fluid in the inlet chamber 41 is thus reduced to a predetermined degree, the spring 52 becomes effective to move the piston valve 44 away from the gasket 55 on the end cover 43 toward the end wall 42 where the piston gasket 5I reseats on the rib 50 and closes off the inlet passage 49 to the inlet chamber 41. As the piston valve 44 moves from the end cover 43 to the end wall 42, in which position it is sho-wn, it uncovers the port 58 and covers the port 51.

The covered port 51 closes off communication between the inlet chamber 41 and the outlet passage 59 so that the timing reservoir 5 is no longer open to the drain valve chamber I4 by way ofthe pipe 32. The uncovered port 58 opens the outlet passage 59 and connected passage '56 to atmosphere by way of the chamber 45 and the atmos pheric vent passage 46, and thereby allows the fluid under pressure in the drain valve chamber I4 to be quickly vented `to atmosphere by way of the drain valve pipe 32 connected to the outlet passage 59 of the timing valve device 6. Upon such reduction in pressure of fluid in the drain valve chamber I4, the springs 28 and 29 become effective to rapidly move the diaphragm I3 and associated valve elements downward toward the casing shoulder 30 until the diaphragm rib 3| reseats thereon. During this motion the double valve element 22 leaves the seat 23 and returns to the seat 24, during which traverse from seat to seat any condensate which has collected in the reservoir 2 or collecting chamber I1 is again rapidly discharged to atmosphere by pressure of fluid in said reservoir through the bore I9, the valve chamber 20, the bore 2I, the exhaust chamber I5 and the pipe and passage I6.

The cycle of operation -of the drain valve apparatus, just described, automatically repeats as uid under pressure -continues to be supplied to the reservoir 2 and to the timing reservoir 5.

In the operation above described, the pressure delivered by the low pressure cylinder 8 of the compressor I may be around 45 pounds, so that the drain valve device 3 must operate at an even lower pressure, and the volume of the reservoir 5 must be such, when charged with fluid, at for instance 40 pounds, as to provide at least said lower pressure in the drain valve device 3 when connected thereto. The size of the choke 38 to permit accumulation of 40 pounds in the timing reservoir may therefore be greater than if the source of supply were of a pressure higher than delivered by the low pressure cylinder, and it follows that the size of the choke 1 may also be correspondingly greater since it must be capable of permitting the pressure in said reservoir to reduce at a rate exceeding the supply through the choke 35. By using larger chokes than could otherwise be used there is less possibility of said chokes becoming clogged and therefore a longer period of trouble free operation of the apparatus is assured.

Summary From the above description it will now be seen that the time required for charging the timing reservoir 5 to the pressure necessary to operate the timing device 6 depends upon the speed of operation of the compressor I, hence the frequency of operation of the drain valve device 3 will vary in accordance with the compressor speed, and therefore in proportion to the amount of condensate which may accumulate in the reservoir 2, so as to ensure the reservoir 2 being maintained substantially free of condensate at all times.

Having now described my invention, what I clai-m as new and desire to secure by Letters Patent, is:

l. In a drain valve apparatus, in combination, a compressor, a receptacle for storing fluid under pressure supplied thereto by said compressor, valve means for controlling discharge of accumulated condensate from said receptacle, fluid pressure motor means for actuating said valve means, a timing reservoir having a restricted communication with said compressor, one way flow means in said communication, means responsive to pressure of fluid in said reservoir for controlling communication of said fluid to said motor means, and means for venting the last mentioned communicationy to atmosphere.

2. In drain valve apparatus, in combination, a fluid compressor, a huid pressure receiver, valve means for controlling drainage of accumulated condensate from said receiver, fluid pressure motor means for actuating said valve means, a fluid pressure timing reservoir having a restricted communication with said compressor, one way flow means in said communication, other valve means operative upon a predetermined increase in pressure of fluid in said reservoir for establishing communication of said fluid to said motor means and for terminating the communication upon a predetermined reduction in pressure of said fluid, and means for electing said reduction.

3. In a drain valve apparatus, in combination, a fluid compressor, a fluid pressure receiver, a drain valve device comprising valve means for controlling discharge of condensate from said receiver, and means responsive to variations in pressure of fluid in a chamber for actuating said valve means, a timing reservoir having a restricted communication with said compressor, a, timing valve device having a fluid pressure inlet which is open to said timing reservoir and a fluid pressure outlet which is open to said chamber and comprising a valve element operative by timing reservoir fluid at a predetermined pressure to establish a communication between said inlet and outlet for supplying fluid under pressure from said timing reservoir to said chamber, said valve element being responsive to a `predetermined reduction in pressure in said inlet to terminate said communication and establish communication between said chamber and atmosphere for venting fluid under pressure supplied thereto, and choke means for eiecting a reduction of fluid pressure in said inlet.

4. In drain valve apparatus, a fluid compressor comprising a high pressure cylinder and a low pressure cylinder, a fluid pressure receiver open to said high pressure cylinder, valve means for controlling drainage of accumulated condensate from said receiver, fluid pressure motor means for actuating said valve means, a timing reservoir having a restricted communication with the low pressure cylinder of said compressor, means responsive to pressure of fluid in said timing reservoir for controlling supply of fluid under pressure from said reservoir to said motor means, and means for releasing uid under pressure from said motor means.

5. In a drain valve apparatus, in combination, a compressor, a receptacle supplied with uid under 'pressure by said compressor, valve means for controlling discharge of accumulated condensate from said receptacle, motor means for actuating said valve means, timing means operable by uid at a chosen pressure to effect operation of said motor means, one-Way flow means for supplying uid under pressure from said compressor to said timing means, and means having greater flow capacity than said one-Way flow means for releasing fluid under pressure from said timing means during operation thereof to eiect operation of said motor means.

6. In a drain valve apparatus, in combination, a compressor, a receptacle for storing uid under pressure supplied thereto by said compressor, valve means for controlling discharge of accumulated r condensate from said receptacle, motor means operable by fluid under pressure to actuate said valve means, one-way iiow means for con- Veying Iiuid compressed by said compressor therefrom, timing valve means subject to pressure delivered through said one-way flow means and REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Name Date Hewitt Aug. 23, 1938 Number 

